Bathroom towel rail and lights circuit

I'm changing a utility room into a bathroom and want to lay out the new electrics to then get them signed off (finally found an electrician willing to do so!). The room requires 5m of cabling to get from the main RCD to the room. I'd like to run an electric towel rail, lighting and extractor fan.

Can someone advise on:
If I can I run this off one circuit?
Whether I need fused, lit, isolator switches for both the rail and the extractor? I assume these need to be outside the room which is very awkward!
Size of electric cable?

Lighting will be led spots and two lamps next to mirror which are IP44 off a transformer.

Thanks!

Probably best to ask your electrician.

Take them off a fused spur

Please bear in mind that this work might notifiable under Part P.

As above ....... your spark should be able to furnish you with all the answers

Thanks all - as I have a friend of a friend doing me a favour in considering reviewing and signing off (not many want to do this which I can understand) I didn't want to make him answer those questions.

And just to be clear, I have applied for building regs approval (we will sell within 2 years, so I'm not naive to not think it matters!) - but I am trying to get a head start.

I'll continue to research until I run out of time and will pay for the rest!